Vowel-to-vowel isochrony is sensitive to syllabic and foot structure

Stefano Coretta

s.coretta@ed.ac.uk

University of Edinburgh

October 30, 2025

Vowel-to-vowel isochrony

Temporal lag between two consecutive vowels is an isochronous unit of speech.

• Coarticulation (Öhman 1966, 1967a, 1967b)

  • VCV sequences.

  • VV stream with superimposed C gestures.

• Rhythm and isochrony (Fowler 1980, 1983, 1992)

  • Stress, syllable, mora isochrony (Abercrombie 1965, 1967; Pike 1945; Ramus, Nespor, and Mehler 1999).

  • Acoustics: they are not isochronous (but see Liu and Takeda 2021).

  • Articulation: continuous production of vowels.

C-centre hypothesis

About the temporal organisation of gestures in relation to syllabic structure.

• Articulatory Phonology: in-phase and anti-phase modes (Browman and Goldstein 1986; Browman and Goldstein 1988, 2000; Goldstein, Byrd, and Saltzman 2006; Goldstein and Pouplier 2014; cf Tilsen 2016).

• The consonantal onset is produced in-phase with the vocalic nucleus, while codas are produced anti-phase.

• Multiple onset consonants are produced in anti-phase with one another and likewise for multiple coda consonants.

Voicing effect and isochrony

Voicing effect as temporal trade-off between vowel and consonant (compensatory adjustment).

• Italian, Polish, English disyllabic words (Coretta 2019a, 2020, 2019b).
• Release-to-release temporal stability.

Syllabic structure

Syllabic structure: Italian

• Celata and Mairano (2014); Celata, Meluzzi, and Bertini (2018); Celata, Meluzzi, and Bertini (2022). Singleton/geminate, tauto- heterosyllabic clusters, but no singleton/tauto comparison?

• Italian as a test case:

  • ✅ Isocrony → tata ~ tatra

  • ❌ tata ~ tatta

  • ❌ tatta ~ tanta

  • ❌ tatta ~ tattra

  • ❌ tanta ~ tantra

Foot structure

• Goldsmith (1990), Hayes (1995), Liberman and Mattingly (1985) : metrical models of segmental organisation.

• Tilsen (2013), Tilsen (2016): hierarchical selection and coordination of speech. Also see Turk and Shattuck-Hufnagel (2020), Elie, Lee, and Turk (2023), Elie, Simko, and Turk (2024), Elie, Šimko, and Turk (2024).

• English:

  • Hayes (1982), Hammond (2003), Jensen (2022): organisation of English foot.

  • Davis and Summers (1989) look at atop/adopt and anti-petting/anti-betting. Inconclusive: possibly no vowel duration difference?

Foot structure: English

• ✅ VV isochrony in atony/atrophy.

• ❌ petition/patrician.

Foot structure: English

• Blaskovics (2025): preliminary findings from articulatory data.

Vowel-to-vowel time lag in within/across feet context and voiceless/voiced consonants (from Blaskovics (2025)).

Summary

• Vowel-to-vowel isochrony is worth investigating (irrespective of traditional rhythmic types).

• I proposed that vowel-to-vowel isochrony is disrupted by:

  • Syllabic structure: codas.

  • Foot structure: across feet.

• Further data needed.

References

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———. 1967. Elements of General Phonetics. Edinburgh: Edinburgh University Press.

Blaskovics, Ákos. 2025. “Vowel-to-Vowel Isochrony Across Different Suprasegmental and Intervocalic Configurations.” PhD thesis, Edinburgh, UK.

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———. 2000. “Competing Constraints on Intergestural Coordination and Self-Organization of Phonological Structures.” Bulletin de La Communication Parlée, no. 5: 2534.

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But not acoustics…

• Blaskovics (2025): very different patters from acoustic data.

Vowel-to-vowel acoustic time lag in within/across feet context and voiceless/voiced consonants (from Blaskovics (2025)).